In general, the wall surface to which mortar is coated is apt to peel-off after a long period of time owing to a peel-off phenomenon caused between the mortar wall surface and the wall itself; and at last the so-called peel-off phenomenon may often be observed. Furthermore, it is necessary to integrate the deteriorating mortar wall surface with the wall itself by filling up the space thus caused owing to the cracked or seceded portion of concrete or bricks by employing a suitable adhesive agent.
According to conventional execution of workings, a number of anchor bolts are knocked into almost the entire area estimated as being destroyed; and thereafter a grout material such as cement mortar is injected into a position or place in the vicinity of the estimated destroyed area. However, in the case of the above conventional execution of workings, it was impossible to retain the mortar wall surface as it was owing to a high pressure action at the time of the injection of the grout material and accordingly a space between the mortar wall surface and the wall itself increased owing to the action of the grout material thus injected, which inevitably caused the enlargement of cracks.